Importance of 4-Aminopyrimidines
4-aminopyrimidines and the aminosubstituted derivatives can be found as structural elements in several antibiotic substances, in herbicides as well as in vitamin B1.
Amprolium (sold as CORID®) for example, thiamin analog, competitively inhibits the active transport of thiamin. The coccidia are 50 times as sensitive to this inhibition as is the host. It can prevent costly coccidial infection in exposed cattle and treat clinical outbreaks when they do occur. By stopping coccidia in the small intestine, CORID® prevents more damaging coccidiosis in the large intestine.
Importance of 4-Amino-5-Aminomethyl-2-Methylpyrimidine
4-amino-5-aminomethyl-2-methylpyrimidine is an important intermediate in the synthesis of vitamin B1. Vitamin B1 (thiamin) is used chiefly in the form of chloride hydrochloride (1) and nitrate.

It is widespread in nature, for example 2.05 mg/100 g wheat germ, 1.3 mg/100 g in soybeans. A deficiency in vitamin B1 in the human being is associated with the disease beriberi, with imbalances in carbohydrate status and deleterious effects on nerve functions. A human being needs 20-30 μg/kg body weight, which corresponds to 0.3-1.5 mg/d daily allowance. Since extraction of thiamin from natural sources would not be economically profitable, it has to be manufactured by chemical synthesis. Industrial production of vitamin B1 started in 1937 by Hoffmann-La Roche in Switzerland and Merck in the United States. Commercially available forms of thiamin are the chloride hydrochloride and the mononitrate.
4-amino-5-aminomethyl-2-methylpyrimidine is a key-intermediate in the synthesis of thiamin which contains a thiazole and a pyrimidine ring. One main approach towards the synthesis of thiamin is the pyrimidine synthesis and subsequent formation of the thiazole ring attached to the pyrimidine moiety from 4-amino-5-aminomethyl-2-methylpyrimidine and 3-chloro-5-hydroxypentan-2-one, the 3-mercaptoketone or the corresponding acetates. Several procedures have been published for the synthesis of 4-amino-5-aminomethyl-2-methylpyrimidine. The building blocks are based on a C2-unit, e.g. acetamidine, and a C1-unit, usually from CO. Acrylonitrile can be used as C3-unit as a cheap starting material for the synthesis.